1. Field of the Invention
Exemplary embodiments of the present invention relate to a key input and management method for seamless cipher communication; and, particularly, to a system in which a transmitter selects an encryption key based on a set time and a receiver selects the same key as the transmitter using the received key select information (one bit) such that the transmitter and the receiver overcome a different key input number, a time difference therebetween, a different transmission delay time and perform seamless cipher communication.
2. Description of Related Art
In order to normally perform cipher communication, both a transmitter and a receiver must communicate using the same key. Furthermore, in order to seamlessly support the cipher communication, each of the transmitter and the receiver must receive a key to use next during the communication, and select a key to use for an actual communication, between the two keys. During this process, the transmitter and the receiver must select the proper key through a method of receiving and managing the two keys, different key input numbers, a time difference between the transmitter and the receiver, different transmission delays and so on, in order to seamlessly perform the cipher communication.
In an existing cipher communication, a transmitter transmits a variety of additional information including time information to a receiver, in order to accomplish the above-described purpose. Furthermore, in order to solve the key mismatch problem, which occurs at a key rotation time due to the time difference between devices and different transmission delays, a plain text is obtained by using both keys for a predetermined time, and a test must be performed on the plain text. Therefore, the efficiency of data transmission/reception decreases, and the processing time increases.